To show the temperature dependence of the harmonic generation process at the
resonant excitation, in Figs. 6, 7 the third harmonic coherent emission rate
in bilayer graphene for various gap energies and various wave intensities
are plotted at the fixed wave frequency \(\omega =\)  \(0.05\)  \(\mathrm {eV/}\hbar \) . The Fig. 6 shows that at the fixed pump wave intensity for a case
of the found optimal value \(U\approx 0.1\)  \(\mathrm {eV,}\)  the third harmonic
emission rate is suppressed with increasing of the temperature. And, as is
seen from Fig. 7, at the same value \(U\approx 0.1\)  \(\mathrm {eV}\) , with the
temperature increase the emission rate of the third harmonic is strictly
diminished, as in intrinsic bilayer graphene at \(U=0\)  [1]} for a small
intensity only. The similar calculations for the intense pump wave or large
gap energy \(U\)  (\(U\gg T\) ) have shown that emission rate exhibits a tenuous
dependence on the temperature.
